Tissue cutter for surgery

Abstract

A surgical cutter is provided for removing body tissue during surgery. The surgical cutter includes a cannula having a proximal end and a distal end and a side wall defining an interior region. The distal end of the cannula is positioned inside a patient's body during surgery with the proximal end situated outside of the patient's body. The side wall of the cannula is formed to include an orifice for receiving body tissue. The surgical cutter further includes a first annular wall fixed to the distal end of the cannula and an annular intermediate wall. The first annular wall is arranged to define an annular gap disposed between the first annular wall and the cannula side wall. The annular intermediate wall includes an annular distal edge sized to be received by the gap. The annular intermediate wall and the cannula are arranged for relative axial movement between a first position with the intermediate wall remote from the orifice and a second position with the intermediate wall received in the gap to cut tissue received in the orifice.

I claim: 
     
       1. A surgical cutter for removal of body tissue during surgery, the surgical cutter comprising a cannula having a proximal end and a distal end and a side wall defining an interior region, the distal end being positionable into a patient's body during such surgery with the proximal end outside of the body, the side wall being formed to include an orifice for receiving body tissue, the orifice having a distal edge,   means for providing suction in the interior region,   a first annular wall fixed to the distal end of the cannula and having a proximal edge, the first annular wall arranged to define an annular gap disposed between the first annular wall and the cannula side wall, and   an annular intermediate wall having an annular distal edge sized to be received by the gap, the annular intermediate wall and the cannula being arranged for relative axial movement between a first position with the intermediate wall remote from the orifice and a second position with the intermediate wall received in the gap to cut tissue received in the orifice.   
     
     
       2. The surgical cutter of claim 1, wherein the first annular wall is disposed within the interior region. 
     
     
       3. The surgical cutter of claim 2, including means for reciprocating the annular intermediate wall between the first position and the second position. 
     
     
       4. The surgical cutter of claim 2, wherein the proximal edge of the first annular wall extends farther in a proximal direction than the distal edge of the orifice. 
     
     
       5. The surgical cutter of claim 1, wherein the distal end of the cannula is formed to include an aperture in fluid communication with the interior region. 
     
     
       6. The surgical cutter of claim 5 including means for providing a liquid solution to the interior region for flow of the solution into the patient's body. 
     
     
       7. The surgical cutter of claim 1, wherein the first annular wall is disposed outside of the side wall of the cannula. 
     
     
       8. The surgical cutter of claim 7, including means for reciprocating the annular intermediate wall between the first position and the second position. 
     
     
       9. The surgical cutter of claim 8, wherein an O-ring sealingly engages the cannula and the annular intermediate wall sealingly engages the O-ring. 
     
     
       10. The surgical cutter of claim 1, wherein the proximal edge of the first annular wall adjacent the orifice extends axially a distance further from the distal end of the cannula than the distal edge of the orifice. 
     
     
       11. The surgical cutter of claim 10, wherein the proximal edge of the first annular wall is arranged to angle away from the orifice toward the distal end of the cannula. 
     
     
       12. The surgical cutter of claim 1, wherein the distal edge of the intermediate annular wall includes a cutting edge. 
     
     
       13. The surgical cutter of claim 12, wherein the cutting edge is prepared by sharpening and electrically etching the distal edge of the intermediate annular wall. 
     
     
       14. The surgical cutter of claim 1, wherein the distal edge of the orifice includes a cutting edge. 
     
     
       15. The surgical cutter of claim 14, wherein the cutting edge is prepared by sharpening and electrically etching the distal edge of the orifice. 
     
     
       16. The surgical cutter of claim 1, wherein the proximal edge of the first annular wall includes a cutting edge. 
     
     
       17. The surgical cutter of claim 16, wherein the cutting edge is prepared by sharpening and electrically etching the proximal edge of the inner wall. 
     
     
       18. A surgical cutter for removal of body tissue during surgery, the surgical cutter comprising an outer cannula having a proximal end, a distal end being positionable into a patient's body during such surgery with the proximal end outside of the body, and a side wall defining an interior region, the interior region defining a cavity in fluid communication with a vacuum source, the side wall being formed to include an orifice arranged to receive body tissue, the orifice having a proximal edge and a distal edge,   an inner cannula having a distal end formed to include a cutting edge and a side wall defining a second interior region, the inner cannula being disposed in the interior region of the outer cannula, the inner cannula and the outer cannula being slidably coupled for relative axial movement between a first position with the cutting edge remote from the orifice and a second position with the cutting edge adjacent the distal edge of the orifice, the inner cannula and the outer cannula being movable between the first position and the second position so that the cutting edge passes the orifice, and   an annular blade including a proximal edge disposed at the distal end of the outer cannula adjacent the orifice, the proximal edge of the annular blade arranged to oppose the cutting edge, the annular blade being arranged so that the annular blade is positioned inside of the second interior region when the inner cannula is in the second position.   
     
     
       19. The surgical cutter of claim 18, wherein the outer cannula is fixed to the surgical cutter and the inner cannula reciprocates between the first position and the second position. 
     
     
       20. The surgical cutter of claim 18, wherein the proximal edge of the annular blade adjacent the orifice extends axially a distance further from the distal end of the outer cannula than the distal edge of the orifice. 
     
     
       21. The surgical cutter of claim 20, wherein the proximal edge of the annular blade is arranged to angle away from the orifice toward the distal end of the outer cannula. 
     
     
       22. The surgical cutter of claim 18, wherein the distal end of the outer cannula is formed to include an aperture in fluid communication with the cavity. 
     
     
       23. The surgical cutter of claim 22, wherein the cavity is in fluid communication with a liquid or gaseous solution source for flow of the solution into the patient's body. 
     
     
       24. The surgical cutter of claim 18, wherein the cutting edge is prepared by sharpening and electrically etching the distal end of the inner cannula. 
     
     
       25. The surgical cutter of claim 18, wherein the proximal edge of the annular blade includes a second cutting edge. 
     
     
       26. The surgical cutter of claim 25, wherein the second cutting edge is prepared by sharpening and electrically etching the proximal edge of the annular blade. 
     
     
       27. The surgical cutter of claim 18, wherein the distal edge of the orifice includes a third cutting edge. 
     
     
       28. The surgical cutter of claim 27, wherein the third cutting edge is prepared by sharpening and electrically etching the distal edge of the orifice. 
     
     
       29. A surgical cutter for removal of body tissue during surgery, the surgical cutter comprising an inner cannula having a proximal end, a distal end being positionable into a patient's body during such surgery with the proximal end outside of the body, and a side wall defining an interior region, the interior region defining a cavity in fluid communication with a vacuum source, the side wall being formed to include an orifice arranged to receive body tissue, the orifice having a proximal edge and a distal edge,   an outer cannula having a distal end formed to include a cutting edge and a side wall defining a second interior region, the inner cannula being disposed in the second interior region of the outer cannula, the inner cannula and the outer cannula being slidably coupled for relative axial movement between a first position with the cutting edge remote from the orifice and a second position with the cutting edge adjacent the distal edge of the orifice, the inner cannula and the outer cannula being movable between the first position and the second position so that the cutting edge passes the orifice, and   an annular blade including a proximal edge disposed at the distal end of the inner cannula adjacent the orifice, the annular blade arranged to oppose the cutting edge, the annular blade being arranged so that the annular blade is positioned outside of the outer cannula when the outer cannula is in the second position.   
     
     
       30. The surgical cutter of claim 29, wherein the inner cannula is fixed to the surgical cutter and the outer cannula reciprocates between the first position and the second position. 
     
     
       31. The surgical cutter of claim 29, wherein an O-ring sealingly engages the inner cannula and the outer cannula sealingly engages the O-ring. 
     
     
       32. The surgical cutter of claim 29, wherein the distal end of the inner cannula is formed to include an aperture in fluid communication with the cavity. 
     
     
       33. The surgical cutter of claim 32, wherein the cavity is in fluid communication with a liquid or gaseous solution source for flow of the solution into the patient's body. 
     
     
       34. The surgical cutter of claim 29, wherein the cutting edge is prepared by sharpening and electrically etching the distal end of the outer cannula. 
     
     
       35. The surgical cutter of claim 29, wherein the proximal edge of the annular blade includes a second cutting edge. 
     
     
       36. The surgical cutter of claim 35, wherein the second cutting edge is prepared by sharpening and electrically etching the proximal edge of the annular blade. 
     
     
       37. The surgical cutter of claim 29, wherein the distal edge of the orifice includes a third cutting edge. 
     
     
       38. The surgical cutter of claim 37, wherein the third cutting edge is prepared by sharpening and electrically etching the distal edge of the orifice. 
     
     
       39. A tissue cutter for use during surgery comprising a pair of concentrically arranged cannula forming a concentric gap between the innermost and the outermost cannula, the innermost cannula providing a first cutting edge opening into the gap, and   a third cannula movable relative to the pair of cannula into the gap, the third cannula having a second cutting edge to cooperate with the first cutting edge.   
     
     
       40. The tissue cutter of claim 39, wherein the second cutting edge is prepared by sharpening and electrically etching the third cannula. 
     
     
       41. The tissue cutter of claim 39, wherein the first cutting edge is prepared by sharpening and electrically etching the innermost cannula. 
     
     
       42. The tissue cutter of claim 39, wherein the outermost cannula is formed to include an orifice sized to accept body tissue and the orifice includes a proximal edge and a distal edge and the distal edge is positioned to lie adjacent to the first cutting edge. 
     
     
       43. The tissue cutter of claim 42, wherein the distal edge of the orifice includes a third cutting edge. 
     
     
       44. The tissue cutter of claim 43, wherein the third cutting edge is prepared by sharpening and electrically etching the distal edge of the orifice. 
     
     
       45. The tissue cutter of claim 39, wherein the outermost cannula includes a side wall arranged to define an interior region that is in fluid communication with a source chamber. 
     
     
       46. The tissue cutter of claim 45, wherein the source chamber is a vacuum source for providing suction to the interior region. 
     
     
       47. The tissue cutter of claim 45, wherein the source chamber is a liquid solution source arranged to provide solution to the interior region for flow of the solution into the patient's body. 
     
     
       48. The tissue cutter of claim 45, wherein the innermost cannula is formed to include an aperture adjacent to the side wall and in fluid communication with the interior region. 
     
     
       49. The tissue cutter of claim 39, wherein the innermost cannula is fixed to the tissue cutter. 
     
     
       50. The tissue cutter of claim 39, wherein the pair of concentrically arranged cannula are fixed to the tissue cutter.